Answer:
When it comes to me, you go on red and stop on green. What am I?
I am a pretty one, fluttering in the pale blue sky. Delicate, fragile on the wing, indeed I am a pretty thing. What am I?
I build up castles. I tear down mountains. I make some men blind, but I help others to see. What am I?
I go in dry and come out wet. The longer I stay in the stronger my surroundings get.
I am a table you can eat. What am I?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.